1. Field of the Invention
The present invention relates to an upright vacuum cleaner, and more particularly, to a height adjusting apparatus for a suction brush of an upright vacuum cleaner, by which a user can facilely adjust a gap between the suction brush and a surface (hereinafter, called 'cleaning surface) of an object to be cleaned.
2. Description of the Related Art
Generally, an upright vacuum cleaner includes a main body having a driving motor for generating a suction force, and a suction brush disposed at a lower side of the main body to be rotated at a desired angle.
In the main body, there are provided a filtering means and a dust collecting container, etc. Foreign substance sucked through the suction brush by the suction force of the driving motor is filtered by the filtering means and then collected in the dust collecting container.
Furthermore, on an upper portion of the main body, there is provided a handle with an on/off switch. Therefore, a user grasps the handle and moves the vacuum cleaner along a cleaning surface. Then, the dust or foreign substance on the surface of the object to be cleaned is sucked through the suction brush.
In this upright vacuum cleaner, there is provided a height adjusting apparatus for adjusting a height between the suction brush and the cleaning surface. Such height adjusting apparatus is classified into various types such as a lever type, a knob type, etc.
The lever type is operated by a user's foot, as described in Korean Patent Laid-Open Publication No. 2001-0012060. Since the lever type is operated by the user's foot, it is easy to adjust the height. However, its components may be complicated, and the apparatus may be also damaged by excessive force due to the using of foot.
The knob type is described in Korean Patent No 1986-001635 as an example. In this knob type, the user rotates a knob with his/her hand to lift up and down a shaft supporting a front wheel of the vacuum cleaner and thus adjust the height of the suction brush. It is easy to use, but there is a problem that, since the height of the suction brush is easily changed by an external impact, it is difficult to expect the apparatus to be stably operated. In other words, there is provided a stepped portion at a bottom surface of the knob so as to lift up and down the shaft. Since an elastic member for supporting the shaft tends to easily lose its supporting force by the external impact, when the suction brush is bumped against a wall or an obstacle during a cleaning operation, the knob is optionally rotated, so that the height adjusted by the user is changed. Therefore, there is an inconvenience that the user has to adjust the height of the suction brush again.